build: Store kotlin-compiler repo URL in a project property

backend.native/build.gradle

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 buildscript {
    repositories {
        mavenCentral()
@@ -16,30 +32,10 @@ apply plugin: 'java'
 apply plugin: 'kotlin'
 apply plugin: org.jetbrains.kotlin.NativeInteropPlugin
 
-
-
-/*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
 // (gets applied to this project and all its subprojects)
 allprojects {
     repositories {
-        //maven { url 'http://dl.bintray.com/jetbrains/kotlin-native-dependencies' }
-        //maven { url 'http://oss.sonatype.org/content/repositories/snapshots' }
-        maven { url 'http://dl.bintray.com/kotlin/kotlin-dev' }
+        maven { url kotlinCompilerRepo }
     }
 
     configurations.all {